| errors | Package errors implements functions to manipulate errors. |
| golang.org/x/text/cases | Package cases provides general and language-specific case mappers. |
| golang.org/x/text/runes | Package runes provide transforms for UTF-8 encoded text. |
| golang.org/x/text/transform | Package transform provides reader and writer wrappers that transform the bytes passing through as well as various transformations. |
| golang.org/x/text/unicode/norm | Package norm contains types and functions for normalizing Unicode strings. |
| golang.org/x/text/width | Package width provides functionality for handling different widths in text. |
| unicode | Package unicode provides data and functions to test some properties of Unicode code points. |
| unicode/utf8 | Package utf8 implements functions and constants to support text encoded in UTF-8. |